In general, a flat-plate solid electrolyte fuel cell (also referred to as solid oxide fuel cell (SOFC)) is composed of: a plurality of plate cells each as a power generation element composed of an anode (negative electrode), a solid electrolyte, and a cathode (positive electrode); and separators (also referred to as interconnectors) disposed between the plurality of cells. The separators are disposed between the plurality of cells in order to mutually and electrically connect the plurality of cells in series, and separate gases supplied to each of the plurality of cells, specifically, separate a fuel gas (for example, hydrogen) as an anode gas supplied to the anode and an oxidant gas (for example, air) as a cathode gas supplied to the cathode. In addition, the separators have a conductor disposed for mutually and electrically connecting the plurality of cells in series. Specifically, the conductor is composed of an anode contact in contact with the anode, a cathode contact in contact with the cathode, and a filling material disposed in the separators for connecting the anode contact and the cathode contact.
For example, Japanese Patent No. 3576881 (hereinafter, referred to as Patent Document 1) discloses a connection body for a solid oxide fuel cell.
The connection body for a solid oxide fuel cell, which is disclosed in Patent Document 1, is composed of an anode filling material disposed on the anode side in a connection hole of a gas separator plate, a cathode filling material disposed on the cathode side in the connection hole, an anode contact for connecting the anode and the anode filling material, and a cathode contact for connecting the cathode and the cathode filling material. The anode filling material and the cathode filling material are formed from different compositions. The anode contact and the anode filling material are equal or substantially equal in coefficient of thermal expansion. The cathode contact and the cathode filling material are equal or substantially equal in coefficient of thermal expansion. The anode contact is composed of nickel, a high-chromium alloy mixture referred to as PLANSEE (trade name), a silver-palladium alloy, or doped lanthanum chromite (hereinafter, abbreviated as LSMC). The anode filling material is composed of a silver-palladium alloy, nickel, or a mixture of PLANSEE and LSMC. The cathode contact is composed of a silver-palladium alloy, lanthanum strontium manganite (hereinafter, abbreviated as LSM), or lanthanum strontium cobaltite (hereinafter, abbreviated as LSCo or LSC). The cathode filling material is composed of LSM, PLANSEE, or a mixture of LSMC and LSCo.
Patent Document 1: Japanese Patent No. 3576881